To protect against product damage by mechanical, physical, and chemical influences from the outside, various coating layers or coating films are applied on the surface of electrical and electronic devices such as mobile phones, electronic components, home appliances, automobile interior/exterior parts, plastic molded products, and the like. However, since scratches on the surface of product coating or cracks due to external impact lower appearance properties, performance, and cycle life, various studies are progressing to protect a product surface to maintain product quality for a long period of time.
Particularly, studies on coating materials having self-healing capability are actively progressing because they do not require an additional coating or repair process even when the surface is damaged, and are extremely favorable for appearance and performance maintenance of products. As a result of these studies, UV curable compositions using self-healing oligomers and inorganic particle or fluorinated compound-added compositions for improving scratch resistance and anti-pollution have been suggested, but coating materials obtained from the compositions may not have sufficient surface hardness and self-healing capability.
Further, previously known coating materials using urethane resin are two-component types of solutions thus requiring a process of combining two kinds of materials, they have low storage stability in a combined state, and the curing time is several tens of minutes.
A coating composition including a polymer or an active polymer material, or including particles or capsules treated therewith on the surface have been suggested. Although a coating layer using the composition exhibits self-healing capability to external impact, it does not have sufficient mechanical properties such as scratch resistance or durability, and compatibility between each component is low.
Recently, it has been suggested that if a coating material including a polyrotaxane compound is used, a coating film or a coating membrane having self-healing capability may be provided, and various methods are being attempted to apply the polyrotaxane compound in coating of automobiles or electronic products, and the like to commercialize it.
For example, WO2005-080469 describes substituting hydroxyl groups of a cyclic molecule α-cyclodextrin with hydroxypropyl groups or at a high substitution rate of methyl groups to improve properties of polyrotaxane.
WO2002-002159 describes crosslinking cyclic molecules α-cyclodextrin) of polyrotaxane using polyethylene glycol.
WO2007-026578 describes a method for preparing polyrotaxane that can be dissolved in toluene or ethyl acetate by substituting hydroxyl groups of α-cyclodextrin with hydrophobic groups of ε-caprolactone, and WO2010-092948 and WO2007-040262 describe paint including polyrotaxane wherein hydroxyl groups of α-cyclodextrin are substituted by hydrophobic groups of ε-caprolactone.
WO2009-136618 describes polyrotaxane wherein a part or all of the hydroxyl groups of the cyclic molecule α-cyclodextrin are substituted by residues of an organic halogen compound to form a radical polymerization initiation part.
However, to prepare previously known polyrotaxane compounds, a synthesis process consisting of many steps should be conducted, or synthesis conditions of high temperature/high pressure while using very limited solvents are required.
Further, coating materials using previously known polyrotaxane compounds do not have sufficient mechanical properties required for a coating material, such as scratch resistance, chemical resistance, and abrasion resistance, or do not have sufficient self-healing capability to scratches or external damage, and thus have limitations in commercialization.